There are a number of instances where prior art proposes various forms of handle adjustability ranging from semi-permanent fixing means U.S. Pat. No. 3,833,219 Sept. 3rd 1974 to, rapidly movable slidable means for length adjustment with annular spacers (washers) proposed for perimetric handle grip size adjustment in one direction only U.S. Pat. No. 3,931,968 Jan. 13, 1976. A study of these and other art reveals that there are serious impracticalities or deficiencies which can be summarized as follows:
Too many round and other openings made into the shafts and handles cause structural weakness. Numerous access holes and wide long gaps between the cover material pieces expose metal screw head and nut parts along with wide gaps between the two handle pallets caused by the annular spacers, present a very broken rough uncomfortable surface for the hand to hold on to. It is difficult to apply the conventionally spirally wound cover materials over the numerous openings and further problems arise to gain access to numerous attaching screws operating levers etc.
The rapidly slidable handles must be rather loose in order to quickly and freely be moved. They require either, tiring sustained hand pressure to keep the handles secure in position on the shaft during play or in another version intermittent pressing of a lever is required to release the handle for length adjustment during play.
Keeping the hand in position to operate the release lever and button interferes with hand positions and changes required for the different serve, forehand, back hand and spin strokes. In the first version just relaxing the hand will cause the handle to slide loosely on the shaft. In the second version an inadvertent touch of pressure will cause the handle to slide loosely on the shaft at the most undesired time.
Clearly this extreme degree of rapid adjustability during play is undesirable. Such a method and control seriously hampers concentration on and achievement of the best hand positioning required for various strokes. The generally very large increase in the number of parts needed complicates and increases the cost of manufacturing such handles to a point of impracticability.